According to recent studies on resurgence scenario of quantum systems, some topological objects with fractional charges play an important role to see the resurgence structure. In this talk, we report a numerical evidence of the fractional-instantons of the SU($3$) gauge theory. The fractional-instanton appears in a weak coupling regime, if the theory is regularized by an infrared (IR) cutoff via the $1$-form twisted boundary conditions. The Polyakov loop is also measured to investigate the center symmetry and confinement. The fractional-instanton corresponds to a solution linking two of degenerate $mathbb{Z}_3$-broken vacua in the deconfinement phase. This talk is based on the paper[1].